javascript - 我们如何使颜色比jquery中的给定颜色更暗

Question

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Answer 1

在这种情况下不需要 jQuery!

function ColorLuminance(hex, lum) {
    // validate hex string
    hex = String(hex).replace(/[^0-9a-f]/gi, '');
    if (hex.length < 6) {
        hex = hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2];
    }
    lum = lum || 0;
    // convert to decimal and change luminosity
    var rgb = "#", c, i;
    for (i = 0; i < 3; i++) {
        c = parseInt(hex.substr(i*2,2), 16);
        c = Math.round(Math.min(Math.max(0, c + (c * lum)), 255)).toString(16);
        rgb += ("00"+c).substr(c.length);
    }
    return rgb;
}

hex为十六进制颜色值，lum为亮度因子，-1 <= lum <= 1，负数表示较暗，正数表示较亮

用法:

var newColor = ColorLuminance("#00ff00", -0.5); // "#334d66" - 50% darker

查看 working JSFiddle

来自 here 的代码片段